Video signals, especially those which are transmitted by satellite, can be corrupted by impulse noise. The impulse noise can appear on the video signal as one or more pulses. These noise pulses cause problems if they resemble the synchronization component of the video signal. The noise pulse is sliced by the sync separator and will produce erroneous timing information. While there are known systems which have attempted to solve this problem, there is a need for circuitry which can reject this type of interference. Furthermore, such a circuit should be amenable to fabrication as a monolithic integrated circuit.
It is known that modern silicon processes which are used for producing monolithic integrated circuits do not provide good control of integrated capacitors. Typically, known processes will produce a tolerance of .+-.20%. One approach to solving this tolerance problem involves designing circuits that depend on ratios of capacitors instead of their absolute values. However, many circuits do not lend themselves to such design parameters and therefore are still affected by variance in the tolerances associated with the silicon processes. Accordingly, there is a need for a circuit which improves the dependence on the tolerance of absolute capacitor values.